Cefotaxime-, Ciprofloxacin-, and Extensively Drug-Resistant Escherichia coli O157:H7 and O55:H7 in Camel Meat

Abstract

The present study aimed to explore for the first time the occurrence and the antimicrobial resistance profiles of E. coli O157:H7 and O55:H7 isolates in camel meat in Egypt. Among the 110 camel meat samples examined using standardized microbiological techniques, 10 (9.1%) and 32 (29.1%) were positive for E. coli O157:H7 and E. coli O55:H7, respectively. In total, 24 isolates were verified as E. coli O157:H7, while 102 isolates were confirmed serologically as E. coli O55:H7. Multiplex PCR revealed the existence of eaeA, stx1, stx2, and EHEC-hlyA among E. coli O157:H7 and O55:H7 isolates (n = 126) at various percentages. According to their resistance against 14 antibiotics, 16.7% and 83.3% of O157:H7 isolates and 8.6% and 76.5% of O55:H7 isolates were classified into extensively drug-resistant and multi-drug-resistant, respectively, whereas 29.4% and 22.2% of E. coli isolates were resistant to cefotaxime and ciprofloxacin, respectively. The study results emphasize that camel meat may be a vehicle for multi- and extensively drug-resistant E. coli O157:H7 and O55:H7 strains, indicating a potential threat to public health. Further studies based on the molecular evidence of the antimicrobial resistance genes and enrolling a larger number of samples are recommended for a better understanding of the antimicrobial resistance phenomenon of camel-meat-originating pathogenic E. coli strains.

Keywords: PCR; Shiga toxins; antimicrobial resistance; camel meat; virulence genes.

Figure 1

Number of camel meat samples contaminated with Escherichia coli O157:H7 and Escherichia coli O55:H7, from the total of 110 investigated.

Figure 2

Representative agarose gel electrophoresis image for PCR amplicon of the rfbO157 gene (800 bp) characteristic for Escherichia coli O157:H7 (Panel (a)) and for the multiplex PCR products of stx1 (614 bp), stx2 (779 bp), eaeA (890 bp), and hlyA (165 bp) virulence genetic markers in both E. coli O157:H7 and E. coli O55:H7 (Panel (b)). M, 100 bp ladder as a molecular DNA marker; Lane C–, PCR runs resulted from using a template of E. coli K12 DH5α genome as a negative control strain (does not harbor any virulence gene); Lane C+, control positive E. coli O157:H7 Sakai as positive reference strain for rfbO157 gene (a) and stx1, stx2, eaeA, and hlyA genes (b). Lanes 1–10 representative isolates for the 10 O157:H7-positive camel meat samples. Lanes A (O157:H7, group A; 13 isolates positive for stx1, stx2, eaeA, and hlyA genes); Lane B (O157:H7, group B; 6 isolates positive for stx2, eaeA, and hlyA genes); Lane C (O157:H7, group C; 3 isolates positive for stx2 and eaeA genes); Lanes D (O157:H7, group D; 2 isolates positive for stx1, stx2, and eaeA genes). Lane I (O55:H7, group I; 46 isolates positive for stx2 and eaeA genes); Lane II (O55:H7, group II; 21 isolates positive for stx2, eaeA, and hlyA genes); Lane III (O55:H7, group III; 12 isolates positive for stx1, stx2, and eaeA genes); Lane IV (O55:H7, group IV; 10 isolates positive for stx2 and hlyA genes); Lane V (O55:H7, group V; 5 isolates positive for stx1, stx2, eaeA, and hlyA genes); Lane VI (O55:H7, group VI; 3 isolates positive only for stx2 gene); Lane VII (O55:H7, group VII; 3 isolates positive only for stx1 gene).